Chemistry of carbon compounds – Miscellaneous organic carbon compounds – C-metal
Reexamination Certificate
2000-06-16
2001-06-19
Richter, Johann (Department: 1621)
Chemistry of carbon compounds
Miscellaneous organic carbon compounds
C-metal
C568S001000, C568S006000, C532S001000, C260S001000
Reexamination Certificate
active
06248265
ABSTRACT:
TECHNICAL FIELD
This invention concerns a process in which fluoroaromatic compounds are converted to fluoroaryl Grignard reagents via reaction with hydrocarbyl Grignard reagents, and further processes that utilize these fluoroaryl Grignard reagents.
BACKGROUND
Perfluoroaryl Grignard reagents are useful in the synthesis of metal and metalloid perfluoroaryl compounds. Many preparations of perfluoroaryl Grignard reagents are known in the literature, some of which call for stoichiometric amounts of Grignard reagent and the polyhaloaromatic compound, J. Organomet. Chem., 1969, 18, 263-274, and J. Organomet. Chem., 1968,11,619-622. Others describe the use of excess Grignard reagent,
J. Org. Chem.,
1964, 29, 2385-2389, and
J. Organomet. Chem.,
1969, 19, 191-195. While it will not be considered further here, it should be noted that perfluoroaryl Grignard reagents have been generated in which the perfluoroaryl Grignard reagent is made directly from Mg metal and the polyhaloaromatic compound, as reported in
J. Chem. Soc.,
1959, 166-171, and
J. Org. Chem.,
1964,29,2385-2389. Two U.S. patents describe methods for obtaining perfluoroaryl Grignard reagents, one with the Grignard reagent in excess, U.S. Pat. No. 5,362,423, and the other with the polyhaloaromatic compound in excess, U.S. Pat. No. 5,600,004.
Other fluoroaryl Grignard reagents are also useful in the synthesis of borane compounds, such as the tetraphenylborate anion, tetrakis(o-tolyl)borate anion, tetrakis(m,n-dimethylphenyl)borate anion, and tetrakis [p-(trifluoromethyl)phenyl]borate anion, which are used as cocatalysts in combination with metallocenes for olefin polymerization. See in this regard, U.S. Pat. No. 5,468,819 to Goodall et al.; U.S. Pat. No. 5,621,126 to Canich et al.; and Brookhart et al.,
Organometallics,
1992, 11, 3920.
Separation of unreacted alkyl Grignard reagent and fluoroaromatic compound starting materials from the reaction mixture is often desired, due to their interference in subsequent syntheses, but such separation is not always feasible.
THE INVENTION
This invention makes possible the formation of a fluoroaryl Grignard reagent from a hydrocarbyl Grignard reagent and fluoroaromatic compounds via separate additions of different fluoroaromatic compounds, such that the conversion of hydrocarbyl Grignard reagent to the desired fluoroaryl Grignard reagent is essentially complete, and thus the reaction product is free or essentially free of agents that may negatively affect subsequent reactions.
A first embodiment of this invention entails in step a) forming a mixture comprising (i) hydrocarbyl Grignard reagent, (ii) at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, and (iii) an anhydrous liquid organic reaction medium. The molar ratio of (i) to (ii) is greater than one, such that a reaction product mixture is formed comprising fluoroaryl Grignard reagent and excess hydrocarbyl Grignard reagent. In step b) at least a portion of the reaction product mixture produced in a) is mixed with an amount of at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, at least sufficient to react with the excess hydrocarbyl Grignard reagent, which thereby produces a further reaction product mixture composed predominately of fluoroaryl Grignard reagent and anhydrous liquid organic reaction medium.
Another embodiment of the invention involves a process which comprises a) reacting, in a liquid organic reaction medium, at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, with a stoichiometric excess of a hydrocarbyl Grignard reagent to produce a reaction product mixture comprising fluoroaryl Grignard reagent and unreacted hydrocarbyl Grignard reagent. In step b), at least a portion of the reaction product mixture produced in a) is contacted with a fluoroaromatic compound to convert at least a portion of said unreacted hydrocarbyl Grignard reagent into fluoroaryl Grignard reagent.
Still another embodiment of this invention entails a process which comprises a step b) in which a mixture comprising a fluoroaryl Grignard reagent, a hydrocarbyl Grignard reagent, and a liquid organic medium is contacted with at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, in an amount at least equivalent to the amount of said hydrocarbyl Grignard reagent. The resultant mixture is maintained at a temperature at least high enough to cause hydrocarbyl Grignard reagent to be converted into fluoroaryl Grignard reagent.
In another embodiment of this invention, a) a mixture is formed comprising (i) hydrocarbyl Grignard reagent, (ii) at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, and (iii) an anhydrous liquid organic reaction medium. In this mixture, the molar ratio of (i) to (ii) is greater than one, such that a reaction product mixture is formed comprising fluoroaryl Grignard reagent and excess hydrocarbyl Grignard reagent. In step b), at least a portion of the reaction product mixture produced in a) is mixed with an amount of at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, such amount being in excess relative to the excess hydrocarbyl Grignard reagent such that a further reaction product mixture is produced composed predominately of fluoroaryl Grignard reagent, anhdydrous liquid organic reaction medium, and unreacted fluoroaromatic compound. In step c), a boron trihalide, a boron trihalide-solvent complex, or an alkyl borate is mixed with at least a portion of the reaction product mixture produced in b) in proportions such that a tris(fluoroaryl)borane is produced.
A further embodiment of this invention involves a) forming a mixture comprising (i) hydrocarbyl Grignard reagent, (ii) at least one fluoroaromatic compound in which bonded directly to an aromatic ring are (1) at least two fluorine atoms, or at least two perfluorohydrocarbyl groups, or at least one fluorine atom and at least one perfluorohydrocarbyl group, and (2) at least two hydrogen atoms, or a combination of one halogen atom other than a fluorine atom and at least one hydrogen atom, and (iii) an anhydrous liquid organic reaction medium. The molar ratio of (i) to (ii) added to the mixture is greater than one, such that a reaction product mixture is formed comprising fluoroaryl Gri
Diefenbach Steven P.
Everly Charles R.
Krzystowczyk Niomi L.
Lee John Y.
Lin Ronny W.
Albemarle Corporation
Faulkner Diedra
Pippenger Philip M.
Richter Johann
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